Improve multiplayer connector UX

[orsinium]

• Wait after "confirm" until all other devices press "confirm"
• Ensure that all peers have the same list of peers.
• POSTPONED: Make it a trust network: automatically add and confirm peers on the devices in "waiting after confirm" state if their friends have confirmed it.
• Ensure that the list of apps in launcher only has apps available on all devices #16
• fix ERROR(sudo.get_file_size): not found in launcher in multiplayer.
• Auto-disconnect when all other peers disconnect
• Send disconnect when exiting the emulator with ESC or shutting down device.
• Show disconnect message in launcher
• Handle disconnect during a game
• Disable networking when leaving multiplayer.
• Compare lists of peers by hash, not count
• After sending Ready, ignore requests from devices not on the ready list.